/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.hudi.common.model;

import org.apache.hudi.common.config.TypedProperties;
import org.apache.hudi.common.util.collection.Pair;

import org.apache.avro.Schema;

import java.io.IOException;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import static org.apache.hudi.common.util.ValidationUtils.checkArgument;

/**
 * Record merger that accumulates metadata records.
 */
public class HoodieMetadataRecordMerger extends HoodiePreCombineAvroRecordMerger {

  public static final HoodieMetadataRecordMerger INSTANCE = new HoodieMetadataRecordMerger();

  @Override
  public List<Pair<HoodieRecord, Schema>> fullOuterMerge(HoodieRecord older, Schema oldSchema, HoodieRecord newer, Schema newSchema, TypedProperties props) throws IOException {
    // If the new record is not a delete record, then combine the two records.
    if (newer.isDelete(newSchema, props)) {
      return Collections.singletonList(Pair.of(newer, newSchema));
    }
    checkArgument(older.getRecordKey().equals(newer.getRecordKey()), "Record key must be the same for both records");
    checkArgument(oldSchema.equals(newSchema), "Schema must be the same for both records");
    return Arrays.asList(Pair.of(older, oldSchema), Pair.of(newer, newSchema));
  }
}
